ozone: Introduce ClientPixmap and ClientPixmapFactory for non-GPU processes.

ui/ozone/platform/cast/ozone_platform_cast.cc

Index: ui/ozone/platform/cast/ozone_platform_cast.cc
diff --git a/ui/ozone/platform/cast/ozone_platform_cast.cc b/ui/ozone/platform/cast/ozone_platform_cast.cc
index 60f7c9a901220a23d2ed3f2662da1cdb6a714211..4b15bffd69a85fc620ba4905208f59a1164b3c2a 100644
--- a/ui/ozone/platform/cast/ozone_platform_cast.cc
+++ b/ui/ozone/platform/cast/ozone_platform_cast.cc
@@ -15,6 +15,7 @@
 #include "ui/ozone/public/cursor_factory_ozone.h"
 #include "ui/ozone/public/gpu_platform_support_host.h"
 #include "ui/ozone/public/input_controller.h"
+#include "ui/ozone/public/native_pixmap_client.h"
 #include "ui/ozone/public/ozone_platform.h"
 #include "ui/ozone/public/system_input_injector.h"
 
@@ -92,6 +93,15 @@ class OzonePlatformCast : public OzonePlatform {
   DISALLOW_COPY_AND_ASSIGN(OzonePlatformCast);
 };
 
+class NativePixmapClientCast : public NativePixmapClient {
+ public:
+  NativePixmapClientCast() {}
+  ~NativePixmapClientCast() override {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(NativePixmapClientCast);
+};
+
 }  // namespace
 
 OzonePlatform* CreateOzonePlatformCast() {
@@ -102,4 +112,8 @@ OzonePlatform* CreateOzonePlatformCast() {
   return new OzonePlatformCast(platform.Pass());
 }
 
+NativePixmapClient* CreateNativePixmapClientCast() {
+  return new NativePixmapClientCast;
+}
+
 }  // namespace ui